Balancing transformer



Nov. 3, 1931. B. M. JONES ET AL 1,829,901

BALANC ING TRANSFORMER 7 Filed May 2. 1927 INVENTORS B. M Jones.

J.H erman n.

x Y K ThairAtzornes Patented Nov. 3, 1931 UNITED STATES,

PATENT OFFICE BENSON M. JONES, OF PITTSBURGH, AND JACOB HINTERMANN, OF SWISSVALE,

' PENNSYLVANIA BALANCING TRANSFORMER Application filed May 2, 1927. Serial No. 188,240.

Our invention relates to balancing transformers. Transformers embodying our invention are particularly suitable for, though in no way limited to use in electrical distributing systems provided with diflferential protecting apparatus.

e will describe one form of transforme embodying our invention, and will then point out the novel features thereof in claims.

10* In the accompanying drawings, Fig. 1 is a 1U transformer shown in Fig. 1.

Similar reference characters refer to similar parts in each of the several views.

Referring to the drawings, it will be seen that the balancing transformer D comprises a U- shaped core H having spaced legs H and H and made up of a plurality of magnetizable lamina clamped securely together at points remote from the ends of the legs by some suitable means such as rivets 36. A winding 10 is placed upon one leg H and a winding 11 is placed on the other leg H Located between the legs H and H of the core H is a bridging member K made up of a plurality of magnetizable lamina each desi nated by the reference character 38. The e ges of alternate lamina 35 of the core D are cut away at the confronting face of the legs H and H to provide guiding channels, and alternate lamina 38 of the bridging member K are also cut away so that the member is provided with outstanding fins which are adapted to enter the channels of legs H and H When the bridging member is in place, therefore, the

h lamina 38 of the bridging member K dovetail into the lamina 35 of the core H as best shown in Fig. 2. Bridging member K is circular in form and is provided with outstanding pins whereby the angular position of the brldging member may be adjusted, as by means of a tool S inserted between these pins as indicated by the broken line in Fig. 1. In order to clamp the bridging member K in this ad- 'usted position the lamina of the core H may be clamped rigidly together between plates 39 by means of bolts 40 provided with nuts 40.

Bridging member K is rovided with a plurality of radially extending slots 37 containing a winding 12.

Transformers embodying our invention may be used with the winding 10 operating as a primary and connected with a suitable source of periodic current. The windings 11 and 12 will usually be connected in series to form a secondary. One advantage of ourin vention is that the current delivered by the secondary of the transformer can be conveniently and accurately adjusted to any desired value. To facilitate this adjustment, the winding 10 is provided with a plurality of adjustable taps 53 (Fig. 1) by means of which a rough adjustment may be made. The final adjustment is made by first loosening the nuts 40 on screws 40 and then turning the bridging member K to vary the angle between the plane of the winding 12 and the path of the magnetic flux supplied to the magnetic circuit including the core H and the bridging member K. This variation in theposition of the bridging member K varies the voltage induced in the winding 12 and it is evident that this adjustment may be made by 'in finitely small steps to accomplish an exact adjustment in the current delivered by the transformer secondary. When this adjustment has been completed the bridging memher K is clamped in its adjusted position by drawing up on the nuts 40*. In order to assist in adjusting the position of the bridging member one or both of the legs H H may be provided with a scale 55 co-operating with an index line on the member K. The scales 55 may be calibrated in any suitable units.

Balancing transformers constructed in accordance with our invention are rugged, simple and easy to adjust and the adjustment possible to such transformer is much more accurate than is possible with the balancing transformers hitherto lcnown in this art.

Although we have herein shown and described only one form of transformer embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims withoutdeparting from the spirit and scope of our invention.

Having thus described our invention what we claim is:

1. A transformer comprising a laminated Ushaped core having spaced legs with the edges of corresponding alternate lamina being cut away to form a plurality of guiding slots on the confronting faces of said legs, a rst winding on said core, a circular laminated bridging member carrying a second winding and having alternate lamina eX- tending radially into said guiding channels whereby rotation of the bridging member varies the coupling between the first and second winding, and means for clamping the bridging member in adjusted position.

2. A transformer comprising a magnetizable Ll-shaped core having spaced legs provided on their confronting faces with parallel guiding channels, a first winding on said core, a circular magnetizable bridging member, a second winding carried by said member, and radially extending guiding fins on said member entering said guiding channels to permit manual rotation of the member to vary the coupling between said first and second windings.

3. ii transformer comprising a U-shaped magnetizable core having spaced legs and made up of lamina rigidly fastened together at points remote from the ends of said legs and having the edges of corresponding alternate lamina cut away to form a plurality of guiding channels, a first winding on the core, a circular magnetizable bridging member having diametrically opposite slots provided with a second winding. radially extending guiding fins on the bridging member entering said guiding channels to permit manual rotation of the member to vary the coupling between tne first and second windings, and means for clamping the lamina of the core together adjacent the ends of the legs to fasten the bridging member in its adjusted position by frictional engagement of the lamina of the core with said fins.

i. it transformer comprising a magnetizable core having two spaced legs, a first winding on said core, a magnetizable bridging member mounted to rotate between said legs, a second winding located on said bridging member and rotatable therewith, and outstanding pins on said bridging member adapted to cooperate with a hand tool to rotate said bridging member.

5. A transformer comprising a magnetizable core having two spaced legs, a first winding on said core, a magnetizable bridging member mounted to rotate between said legs, a second winding located on said bridging member and rotatable therewith, and means integral with at least one leg of said core for clamping said bridging member in position.

6. A transformer comprising a magnetizable core having two spaced legs each made up of at least two lamina, a bridging member mounted to rotate between said legs and provided with a fin adapted to enter the channels between the lamina of said legs, means for clamping the lamina of each leg together to hold said bridging member in position, and a second winding located on said bridging member and rotatable therewith.

7. A transformer comprising a magnetizable core having two spaced legs provided on their confronting faces with parallel guiding channels, a first winding on said core, a circular magnetizable bridging member rotatable between said legs and having'radially extending fins adapted to enter said guiding channels, arcuate plates on opposite sides of said legs for preventing removal of said bridging member while permitting free rotation of the member, means for clamping said plates to the corresponding legs of the core, and a second winding located on said bridging member and rotatable therewith.

In testimony whereof we aflix our signatures.

BENSON lWI. JONES. JACOB HINTERMANN. 

